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This invention relates generally to surgical devices. More specifically, the present invention relates to improved sternum clamping devices and methods to reapproximate a patient""s sternum following a partial median sternotomy.
A partial or median sternotomy is a procedure by which a saw or other appropriate cutting instrument is used to make a midline, longitudinal incision along a portion or the entire axial length of the patient""s sternum, allowing two opposing sternal halves to be separated laterally. A large opening into the thoracic cavity is thus created, through which a surgeon may directly visualize and operate upon the heart and other thoracic organs or tissues. Following such a procedure, the two severed sternal halves must be reapproximated.
Traditionally, sternal halves have been reapproximated with stainless steel wires wrapped around or through the sternal halves so as to exert medial compression thereon and twisted together to approximate the sternum. Other methods of sternum repair include the use of band or strap assemblies which typically include a locking mechanism, which secures a strap in a closed looped configuration about the sternum positions. While utilization of steel wires and strap assemblies have been widely accepted for sternum repair, these devices present a number of disadvantages. Steel wires can and do break, and provide insufficient(non-uniform) clamping force resulting in sternal nonunion. Steel wires are difficult to maneuver and place around the sternum. The cut ends of the steel wires are also sharp and can pierce through the surgeon""s gloves or fingers. In addition, the small diameter of the steel wires can cause the wires to migrate into or through the tissue surrounding the sternum region or into the sternal bone itself over time. This can lead to significant patient pain and discomfort in addition to slowing the postoperative recovery and increasing the risk of sternal infection. Moreover, the strap mechanisms of band assemblies are often relatively structurally complex and are difficult to precisely apply about the sternum. There are also healing problems associated with the use of steel wires and band assemblies due to improper forces exerted by these devices which can cause unwanted bone movements leading to raking and rubbing of surrounding tissue or bone.
Several other techniques of sternal reapproximation have been proposed both for primary closure following a median sternotomy and for reclosure following post-operative emergency surgical procedures. One such sternal fixation device is described in U.S. Pat. No. 6,051,007 entitled External Closure Device and Instruments Therefor, the entire contents of which are incorporated by reference. The sternum closure device of U.S. Pat. No. 6,051,007 however is clearly absent the benefits and teachings of the instant invention. Most particularly foot portions (20, 40) of the ""007 device are limited to two points of contact on the posterior section of a patient""s sternum and consequently lack the stability and positioning enhancement features of the instant invention. Quite distinguishable, from the ""007 patent and other devices practiced in the contemporary art is the present invention""s novel structure which allows and encourages divided sternal plates to be tilted upward to maximize healing surfaces in apposition to each other, thus avoiding downward plate deflection and substandard healing. Further, the instant invention spans the width of at least two interspaces, eliminating the need for more than one device for tight/secured closure over the same sternal area. The four securing leg and foot structures of the instant invention improve pulmonary mechanics by assisting in alignment of ribs across the sternotomy allowing for simultaneous right and left rib elevation symmetrically across the sternum and chest. The dual blade structure of the instant invention leverages the tight connections provided by fascia and muscle, strengthens pulmonary compliance and allows for distribution of energy and positioning strength to be spread evenly throughout the sternum. Most distinguishable from the contemporary art, the instant invention enables fragmented segments of the sternum to be held in place for healing, as opposed to single plate structures of the contemporary art which concentrate (as opposed to distribute) energy occassionally to a crushing central point thereby allowing laterally displaced fragments to further displace.
The above is a brief description of some deficiencies in the prior art and advantages of the present invention. Other features, advantages, and embodiments of the invention will be apparent to those skilled in the art from the following description, accompanying drawings and claims.
The present invention provides an improved device and method for reapproximating the sternal halves of a patient""s sternum following a median or partial sternotomy, and facilitates ready access to the thoracic cavity during or after a medical procedure advanced the art by overcoming the sternal nonunion problems inherent in prior art devices.
The present invention advances the present art and provides for an improved sternum clamping device which employs first and second clamp structures; and angled foot members which facilitate tilting divided sternal plates upward in apposition to each other avoiding prevent downward deflection to enhance healing.
Another significant object of the instant invention is to provide for two separate clamping devices from opposing sides which decreases the amount of metal needed for clamping/securing structures.
An additional object of the invention is to provide for two independently adjustable locking means which distribute the strength of a sternum closure, equally and laterally, and essentially appose opposing rib segments along the same plane.
Another object of the instant invention is to provide a device wherein the width of two separate intraspaces associated with the invention""s clamping structures to eliminate the need for multiple devices to facilitate sternum closure over the same area.
Yet another object of the instant invention is to provide for quick release mechanism which will prevent tissue ingrowth into the clamp release mechanism.
A further object of the instant invention is to provide a small locking member and clamping apparatus which results in decreased apparatus profile and weight but not closure strength.
Yet another object of the instant invention is to provide for two member locking mechanism which improves pulmonary mechanics by assisting in the alignment of the ribs across a sternotomy, thus permitting simultaneous right and left rib elevation symmetrically across the sternum and chest.
A further object of the instant invention is to provide for a dual clamp locking mechanism which leverages ribs connected by fascia and muscle strengthening pulmonary compliance.
An additional object of the instant invention is to provide a mechanism and method by which the distribution of closure energy and strength are spread evenly throughout the sternum enabling even fragmented segments of the sternum to be held in place for healing.
Yet another object of the instant invention is to provide an apparatus by which the strength of the sternal closure is actually increased and distributed by means of a double clamping mechanism over a correspondingly positioned rib pair.
An additional further object of the instant invention is to provide an apparatus by which the alignment of apposing ribs actually increases the strength of the closure as well as pulmonary force expiratory volume.
Yet another object of the instant invention is to provide an apparatus in which the edges are smooth to prevent dehiscence or extrusion.
Other objects and further scope of the applicability of the present invention will become apparent from the detailed description to follow, taken in conjunction with the accompanying drawings wherein like parts are designated by like reference numerals.